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321.
P. S. Kulkarni S. V. Kamath H. V. Kamath Sheshgiri N. Kulkarni 《Journal of mass spectrometry : JMS》1984,19(10):482-485
The mass spectral fragmentation of 2,3-diaryl-3-oxo-1-propanals has been investigated by low electron energy, metastable defocusing and shift techniques. The o-nitro group strongly interacts with α-cleavage reactions of the carbonyl group. The cyclization/elimination processes, accompanied by oxygen and hydroxyl transfer in the mass spectra of o-nitro-β-keto aldehydes, are preceded by hydrogen abstraction by the nitro group. 相似文献
322.
Narendra K. Tripathy 《Tetrahedron letters》2004,45(27):5309-5311
An efficient total synthesis of cryptophycin-24 (arenastatin A) is reported, which features two novel synthetic strategies, the use of a RCM reaction to form the macrocycle, and the introduction of the styrene epoxide moiety prior to the macrocyclization reaction. 相似文献
323.
Tris-N(ethyl, m-tolyl) dithiocarbamato complexes of arsenic(III), antimony(III) and bismuth(III) abbreviated as As(S2CNRR′)3 Sb(S2CNRR′)3 and Bi(S2CNRR′)3, respectively, where R C2H5 and R′ m-C6H4CH3, have been synthesized. These complexes have been characterized on the basis of elemental analyses, molecular weight determinations, conductance measurements and infrared spectral studies. Thermal studies of these complexes have been carried out in nitrogen and air to determine their modes of decomposition. Kinetic parameters, such as apparent activation energy and order of reaction, have been determined by the graphical method of Coats and Redfern [1]. 相似文献
324.
325.
Pandurang M. Kamath Anthony Barlow 《Journal of polymer science. Part A, Polymer chemistry》1967,5(8):2023-2030
A careful study of the radiolysis products of a series of ethylene α-olefin copolymers and ethylene homopolymers has shown that if a correction is applied, to take into account the fragments arising from scission at chain ends, the remaining products can be quantitatively accounted for as entirely due to scission of side branches introduced onto the backbone chain by the α-olefin comonomer. The cleavage of branches takes place, for all practical purposes, exclusively at the branch points at which the branches are attached to the backbone chain. The same data together with similar radiolysis data of poly(3-methyl pentene-1) and poly(4-methyl pentene-1) have further shown that all branches cleave with equal efficiency, regardless of their length. Radiolysis does, therefore, provide a reliable and convenient tool for the quantitative characterization of high-pressure polyethylene with regard to the unique short-chain branching distribution that is characteristic of each. 相似文献
326.
Anil P. Kamath Narendra K. Karmarkar K. G. Ramakrishnan Mauricio G. C. Resende 《Mathematical Programming》1992,57(1-3):215-238
In this paper we describe an interior point mathematical programming approach to inductive inference. We list several versions of this problem and study in detail the formulation based on hidden Boolean logic. We consider the problem of identifying a hidden Boolean function:{0, 1}
n
{0, 1} using outputs obtained by applying a limited number of random inputs to the hidden function. Given this input—output sample, we give a method to synthesize a Boolean function that describes the sample. We pose the Boolean Function Synthesis Problem as a particular type of Satisfiability Problem. The Satisfiability Problem is translated into an integer programming feasibility problem, that is solved with an interior point algorithm for integer programming. A similar integer programming implementation has been used in a previous study to solve randomly generated instances of the Satisfiability Problem. In this paper we introduce a new variant of this algorithm, where the Riemannian metric used for defining the search region is dynamically modified. Computational results on 8-, 16- and 32-input, 1-output functions are presented. Our implementation successfully identified the majority of hidden functions in the experiment. 相似文献
327.
The kinetics of the reaction of l-ascorbic acid (H2A) with aquachromium(III) has been studied over the range 0.04 [H2A]T 0.16 mol dm–3, 3.5 pH 6.0, 25.0 t 50.0C, 0.03 I 1.0 mol dm–3 (KNO3) and 0% [MeOH] 20% (v/v). The reaction takes place via an outer-sphere association between Cr3+/CrOH2+ and H2A, followed by transformation of the outer- into an inner-sphere complex by slow interchange. The anation rate constants for Cr3+ and CrOH2+ species (k1 and k2) at 25C and I=1.0moldm–3 (KNO3) are 1.68×10–4 and 2.14×10–4s–1, respectively. H and S for the k1 and k2 paths are 27.0±2kJmol–1, –227±5J K–1mol–1 and 57.2± 4kJmol–1, –123±14JK–1mol–1, respectively. Anation of Cr(H2O)3+6 and Cr(H2O)5OH2+ follow an Ia path. 相似文献
328.
329.
S. Narendra Babu K. Srinivas T. Bhimasankaram 《Journal of magnetism and magnetic materials》2009,321(22):3764-3770
Lead-free multiferroic magnetoelectric composites consisting of ferrimagnetic Ni0.93Co0.02Mn0.05Fe1.95O4 (NMF) and ferroelectric Na0.5Bi0.5TiO3 (NBT) phases were synthesized by the solid-state sintering method. The presence of constituent phases in composites was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A systematic study of dc conductivity as a function of temperature (RT −450 °C) revealed that the conduction is due to small polarons. The effect of constituent phase variation on the dielectric constant and piezoelectric strength (d33) was examined. The composites exhibited typical magnetic hysteresis (M–H) loops at room temperature. Furthermore, magnetoelectric (ME) output was evaluated as a function of applied magnetic field, which is a product property of the constituent phases. The compound 50% NMF–50%NBT is a new lead-free magnetoelectric composite with 155 μV/cm ME output, which may have potential applications. 相似文献
330.
Narendra Chauhan Ankush Mittal Dietmar Wagner M. V. Kartikeyan M. K. Thumm 《International Journal of Infrared and Millimeter Waves》2008,29(8):792-798
In this paper the design and optimization of a nonlinear diameter taper, connecting the output section of a gyrotron cavity
to the uniform output waveguide section, is presented. The design of a nonlinear taper of a 42 GHz, 200 kW CW gyrotron operating
in the TE0,3 cavity mode with axial output collection has been taken as a case study. The taper synthesis has been carried out considering
a raised cosine type of nonlinear taper and the analysis is done using a dedicated scattering matrix code. In addition, an
improved particle swarm optimization - an evolutionary optimization - algorithm is used for the design optimization of this
nonlinear taper. The optimum design of the taper shows the effectiveness of the presented method. 相似文献